Issue #18722: Remove uses of the "register" keyword in C code.
diff --git a/Python/strdup.c b/Python/strdup.c
index 20187e0..769d3db 100644
--- a/Python/strdup.c
+++ b/Python/strdup.c
@@ -6,7 +6,7 @@
 strdup(const char *str)
 {
 	if (str != NULL) {
-		register char *copy = malloc(strlen(str) + 1);
+		char *copy = malloc(strlen(str) + 1);
 		if (copy != NULL)
 			return strcpy(copy, str);
 	}